It comes as far south as Buenos Ayres, but is only a summer visitor there, and very scarce. Having seen but little of it myself, I can only repeat Azara's words concerning it. He says it is common in Paraguay, going in pairs or families, and perches and roosts on trees, and when flying flaps its wings more rapidly than other Herons. It makes its nest on a tree, and lays two clear blue eggs. On the Lower Uruguay, Mr. Barrows likewise found this species "not common." It was only seen a few times in November. "Though most resembling the Night-Heron they were active by day, and when disturbed flew rapidly away from the streams and swamps towards the dry woods and hills." 320. BUTORIDES CYANURUS (Vieill.). (LITTLE BLUE HERON.) +Butorides cyanurus+, _Scl. et Salv. Nomencl._ p. 125; _iid. P. Z. S._ 1868, p. 145 (Buenos Ayres); _Durnford, Ibis_, 1878, p. 62 (Buenos Ayres); _Barrows, Auk_, 1884, p. 271 (Entrerios). +Butorides striata+, _Baird, Brew., et Ridgw. Water-B. N. A._ i. p. 50. _Description._--Glaucous grey; beneath ashy; crown crested, black, with greenish gloss; neck beneath with a band of ferruginous spots, more or less mixed with black; wings greenish cinereous; wing-coverts edged with whitish; bill dusky green, feet ashy yellowish: whole length 14·0 inches, wing 6·5, tail 2·5. _Female_ similar. _Hab._ South America. The Little Blue Heron, though widely distributed, is not anywhere a common bird. I have always seen them singly, for it loves a hermit-life, and the feeding-ground it prefers is a spot on the borders of a marshy stream shut in and overshadowed on all sides by trees and tall rushes. There the bird sits silent and solitary on a projecting root or dead branch; or stands motionless and knee-deep in the water, intent on the small fry it feeds on. For whole months it will be found every day in the same place. When intruded on in its haunt it erects the feathers of its head and neck, looking strangely alarmed or angry, and flies away uttering a powerful harsh grating cry. Its nesting-habits I do not know; but Mr. Barrows says that it undoubtedly breeds near Concepcion on the Lower Uruguay, where it is abundant in spring and summer. 321. ARDETTA INVOLUCRIS (Vieill.). (VARIEGATED HERON.) [Plate XVII.] [Illustration: ARDETTA INVOLUCRIS.] +Ardetta involucris+, _Scl. et Salv. Nomencl._ p. 125; _iid. P. Z. S._ 1869, p. 634; _Hudson, P. Z. S._ 1875, p. 624 (Buenos Ayres); _Durnford, Ibis_, 1877, p. 189, et 1878, p. 62 (Buenos Ayres); _Gibson, Ibis_, 1880, p. 159 (Buenos Ayres); _Barrows, Auk_, 1884, p. 271 (Entrerios).